How many amendments does the Constitution have?

Twenty-seven. The first ten, ratified together in 1791, are the Bill of Rights: speech, religion, press, arms, due process, and the rest of the founding package. The remaining seventeen arrived over two centuries and include the abolition of slavery (13th), birthright citizenship and equal protection (14th), women's suffrage (19th), and presidential term limits (22nd). One amendment exists solely to cancel another: the 21st repealed Prohibition's 18th.

Amending is deliberately brutal: two-thirds of both houses of Congress plus ratification by three-quarters of the states, which is why more than 11,000 amendments have been proposed and 27 have survived.

The 27th has the best origin story in American law. Proposed in 1789, it limited congressional pay raises and then sat dormant for two centuries until a University of Texas student, Gregory Watson, wrote a 1982 paper arguing it could still be ratified, received a C, and launched a one-man national campaign. It passed in 1992. The grade was later officially changed to an A.